PASSIVE RADAR
From the book: CONCISE ENCYCLOPEDIA of SCIENCE AND TECHNOLOGY Fifth Edition
page 1618
("PASSIVE RADAR A receive-only radar used for search, tracking, surveillance, identification, guidance, and mapping. The operation of passive radar depends upon the detection of microwave or infrared radiation from warm bodies. ....
Many potential military targets radiate high noise power, such as ships at sea, exhaust from trucks, tanks, missiles, and airplanes, and factory chimneys. Unlike an active radar, a passive radar cannot determine the range to a target. However, using the high antenna directivity obtainable at microwave and infrared wavelengths, a passive radar can locate a source of radiation accurately in direction and discriminate between nearby targets.
A passive radar can track a target closely and be used to direct weapon fire toward it. A passive radar, mounted on a missile, can be used to home the missile in on a target by using just the pointing information provided by the radar. The power required to operate such a radar is quite small because there is no transmitter. Ground surveillance and mapping can be accomplished with an airborne ground scanner. This type of radar provides an infrared picture of the terrain and any targets which may be present.
The absence of transmitted power makes the location, and even the existence, of a passive radar difficult to determine. Even if the position of a passive radar is known, its frequency cannot be determined; for this reason and because of the high angular resolution, it is difficult to jam.")
For general reference
Bob D.
page 1618
("PASSIVE RADAR A receive-only radar used for search, tracking, surveillance, identification, guidance, and mapping. The operation of passive radar depends upon the detection of microwave or infrared radiation from warm bodies. ....
Many potential military targets radiate high noise power, such as ships at sea, exhaust from trucks, tanks, missiles, and airplanes, and factory chimneys. Unlike an active radar, a passive radar cannot determine the range to a target. However, using the high antenna directivity obtainable at microwave and infrared wavelengths, a passive radar can locate a source of radiation accurately in direction and discriminate between nearby targets.
A passive radar can track a target closely and be used to direct weapon fire toward it. A passive radar, mounted on a missile, can be used to home the missile in on a target by using just the pointing information provided by the radar. The power required to operate such a radar is quite small because there is no transmitter. Ground surveillance and mapping can be accomplished with an airborne ground scanner. This type of radar provides an infrared picture of the terrain and any targets which may be present.
The absence of transmitted power makes the location, and even the existence, of a passive radar difficult to determine. Even if the position of a passive radar is known, its frequency cannot be determined; for this reason and because of the high angular resolution, it is difficult to jam.")
For general reference
Bob D.
Starmail - 27. Feb, 09:21